Video: Cindy Anthony on her 911 calls

Word association: you hear "Orlando" and images explode of castles and rides, Mickey and Minnie, leaping orcas and slack-jawed children dazed with the wonder of it all. It's not much of an overstatement to say that the Orlando economy is all about making kids deliriously happy.

But for millions of TV viewers, since last summer there's one Orlando child, in particular, who's been a reminder that the flipside of children's happiest dreams can be the darkest of nightmares.

By now, you've seen their faces everywhere: Caylee Marie Anthony, the missing two-year-old girl, and her 22-year-old mother Casey. But tonight the question— where is Caylee? – may have been answered in the most unhappy way.

Thursday morning a meter reader for a local utility came upon what thousands of volunteer searchers had missed in the past six months: the skeletal remains of a small child, found in a plastic bag, just a quarter mile from the home where Caylee was being raised by her mother and grandparents.

The bones have not been conclusively identified as Caylee's. But the authorities say evidence found among the remains can be linked to Caylee's home. A weekend and more of testing by the FBI lies ahead. The new question is: is it really Caylee?

Tonight, we'll put the case together starting from the very first hours of this mystery, back weeks ago when we talked to the missing child's grandparents who believed fervently that the child was alive and in danger from unknown kidnappers.

Casey Anthony: I'm never gonna forgive myself because there's that chance that I might not see Caylee again and I don't want to think about that.

So let’s begin here: a quiet, middle-class neighborhood of Orlando, where George Anthony, a former sheriff's deputy now in the security business, and his wife, Cindy, a registered nurse, raised their son, lee, and daughter, Casey.

CindyAnthony: Casey was always a good student. She was always the mom of the crowd. Always took care of everybody and they still call her Mom -- her friends.

After high school, Casey got a job working at the Universal Studios theme park, which is, incidentally, owned by this program's parent company NBC Universal. It was there Casey met a young guy named Jesse Grund.

Jesse Grund: It was kind of the love at first sight type of thing.

Jesse and Casey started dating in January 2005, and their relationship blossomed, though it did come as something of a shock to Jesse when Casey told him six months later that she was pregnant, and that he was the father.

Jesse: My exact words to her were, "I'm not ready to be a parent, and you're not ready to be a parent. Let's give the child up to someone, some family who can't have kids, who is ready to be parents." And she said, "No, I'm not gonna carry this child around for nine months, and give birth to it, and then give it up to somebody else. This is my child."

On August 9th, 2005 little Caylee Marie Anthony was born. Her birth certificate never listed a father -- a paternity test showed that it wasn't Jesse, the boyfriend. It didn't matter. Jesse was as smitten with the baby girl, as he'd been with her mother. Jesse proposed and Casey said “yes.”

Jesse: She was crying. And it was probably one of the happiest moments of my life.

But five months later, Casey -- who was still living with her parents -- broke off the engagement. She told Jesse she was happier on her own. And she did indeed seem happy. She took to motherhood with apparent joy.

And her parents couldn't have been more supportive. To them, Caylee's arrival seemed like a gift from heaven.

Cindy: Oh, absolutely. I mean, she lights the room and she controls the house.

All of which makes the events of last Father's Day weekend, when Caylee Anthony suddenly disappeared -- that much more of a mystery.

That Sunday, June 15th, grandmother Cindy took Caylee to visit her great grandfather in his nursing home. This home video, taken during that visit -- contains the last confirmed pictures we have of Caylee.

Cindy: We spent a wonderful day together, and then Casey came home and we had a great evening that evening.

The next morning, Monday, George remembered seeing Casey and Caylee at home before he left for work.

George: I was still home in the morning getting ready to go do my job, you know, later that afternoon.

Dennis Murphy: She's not coming to her bedroom and the child is gone and...

Cindy: Right, and you know, she had an explanation every day where she was. And a reasonable explanation.

But four weeks later, she was still a no-show when on July 15th, George received notice that their car -- the white Sunfire Casey had been driving -- had been towed. She'd abandoned the vehicle two weeks earlier, in the parking lot of a check cashing business.

Orlando Sentinel Reporter Bianca Prieto: That's when it's like, "Oh my gosh, Casey's car's been towed. What's going on?" And so, they go to pick it up. They get there and they say there's this overwhelming stench just coming from the car. You're three feet away and you can smell it.

George, the former sheriff's deputy, later told investigators that he knew the odor well.

George: It smelled, uh, like a decomposed body. I'm being very straight with you guys. I've got a sick feeling for a second because the car that was all closed up, if you're in, from me to you away from it, you can smell an odor, you don't forget that odor, no matter what it is, you never, ever forget it.

After retrieving the car, Cindy Anthony decided to take action -- she was determined to confront Casey face-to-face. But where was she?

Cindy: I had found a resume of one of her friends in the front seat. So, I just took her phone number off of there and actually when I called her, was very surprised that she had seen Casey just hours before.

The friend told Cindy she knew where Casey was staying that day, and agreed to take Cindy there.

Cindy: When Casey came to the door, you know, I asked her where Caylee was. She said she was with the nanny. I said, "Let's go pick up Caylee." And she said, "No, mom, you know, it's kinda late in the evening.

Cindy: I said, "One of two things is happening. You know, either we're gonna drive to, you know, pick up Caylee or I'm gonna take you to the police station and someone else is gonna help me pick up Caylee." And she said, "Mom," she says, "It's okay. Take me.”

Dennis Murphy: Take me to the police?

Cindy: Yes. And for her to say it, you know, to take her, I'm thinking now, "Something’s not right."

Cindy was about to find out how "not right" things were. She took Casey back home, and from there, she dialed 911.

Cindy: I have someone here that I need to uhm, be arrested in my home.

Operator: They're there right now?

Cindy: And I have a possible missing child. I have a three-year-old that's been missing for a month.

Operator: A three-year-old?

Cindy: Yes.

Operator: Have you reported that?

Cindy: I'm trying to do that now, ma'am.

But shortly after that 911 call, Cindy says she overheard Casey whispering something to her brother, Lee... Something about a babysitter, Zanny, that would set her into full-on panic mode.

Cindy: I heard her say the words that Zanny had taken Caylee. And that's when I flew into her room. And I said, "What the heck are you talking about?" And she just broke down and she said it had been, 31 days that she had seen her daughter.

After 30 days with no sign of her grandchild, Cindy Anthony had finally confronted her daughter, Casey, and heard a truly disturbing story. That someone named Zanny, a woman who Casey said she'd hired as an occasional babysitter, had kidnapped little Caylee.

Cindy: That's when I, you know, I panicked and I got on the phone. And I didn't care what the heck I said to get them out there.

Cindy: That the baby-sitter took her a month ago. The daugh... my daughter's been looking for her. I told you my daughter was missing for a month. I just found her today but I can't find my granddaughter. And she just admitted to me that she's been trying to find her herself. There's something wrong. I found my daughter's car today and it smells like there's been a dead body in the damn car.

Dennis Murphy: That's a very alarming bit of information for a 911 dispatcher.

Ron Stucker: That is.

Ron Stucker is chief of criminal investigations at the Orange County sheriff's office.

Dennis Murphy: Deputies arrive at the house and say, "What do you have here?"

Ron Stucker: What they find out is they're getting really mixed stories and conflicting information.

The story investigators got from Casey is that one month before, she'd dropped Caylee off with her baby-sitter -- Zenaida Fernandez-Gonzalez -- before heading to work at Universal Studios. When she returned to pick Caylee up, no one was home.

Bianca Prieto: No, she doesn't call anybody. She says that she sits there for a few hours on the steps waiting, and then decides to do her own investigation.

Dennis Murphy: She's been unaccounted for more than 30 days at this point.

Ron Stucker: It's incredible --

Dennis Murphy: That's gotta be hugely unusual in this kind of case.

Ron Stucker: Incredible disadvantage for us.

That disadvantage was about to get a whole lot worse. Deputies, with Casey, in tow began looking for this baby-sitter, Zenaida. They drove Casey to the apartment where she said she'd left Caylee with the sitter. But the apartment, it turned out, had been vacant for almost five months.

Casey then led detectives on what turned out to be a wild goose chase around Orlando-- she pointed out an apartment building where she says Zenaida had lived two years ago. It turned out to be a seniors-only facility.

Then she brought them to a building where she says Zenaida's mother owned a condo -- but no one in the building knew the babysitter or her mother.

The investigators then returned to the first apartment building to go through the residents list. There was no Zenaida Fernandez-Gonzalez living there, but they did locate a Zenaida Gonzalez who had applied to rent an apartment back in June.

Zenaida Gonzalez: They called my cell phone. And then they asked me, they first asked me -- "Are you Zenaida Gonzalez?" Yes.

To this day, this Zenaida isn't sure how Casey got her name -- whether it was just coincidence, or if Casey may have come across the visitor's log at that apartment building. But Zenaida told investigators she'd never heard of Casey, and was most certainly not a baby-sitter... And the sheriff's office believed her.

Zenaida Gonzalez: I got six kids of my own, what you think, I want to bring another one into the family? I'm OK. (laughter) I have enough. I have enough.

Every possible lead that Casey Anthony had given investigators turned out to be a dud. The apartment where she claimed she'd dropped Caylee off -- vacant. The baby-sitter -- a phantom. And there was something else -- there was no evidence that Casey had told anyone about her daughter's disappearance over the last month.

By now, detectives were certain that Casey Anthony was spinning a web of lies. They were ready to confront her at the last stop on their Orlando tour -- the Universal Studios theme park.

With her story unraveling, Casey accompanied investigators to the employee entrance at Universal Studios, telling the security guard she'd lost her ID.

Ron Stucker: And we said, "Well, go ahead and let her in. Let's just go walk down to her office." She walked with the detectives down a hallway and just walked down looking in offices and --

DennisMurphy: You got a breakthrough moment at that point, didn't you, Chief?

Ron Stucker: She reached the end of the hallway and she turned around. And when she ran out room -- and she said, "I'm lying to you. I don't work here."

She had once... But not for years. During a recorded conversation in a conference room at the theme park, casey broke down and confessed that she had been lying.

Police: Okay, so you purposely misled us. This was all an attempt to help find your daughter, right? That makes sense to you, correct?

Casey: Again and in a backwards sort of way, yes.

Caught in a lie but still she stuck to her original story -- that a baby-sitter named Zenaida Fernandez-Gonzalez had indeed kidnapped Caylee.

Casey: I saw my mom's reaction right off the bat and it would've been the same from the get-go.

Police: So wait a minute. So you're more afraid of your mom's reaction than you are if you ever see your daughter again?

Casey: No, I'm absolutely petrified. Absolutely petrified. I know my mom will never forgive me. I'm never gonna forgive myself because there's that chance that I might not see Caylee again and I don't want to think about that.

She forged on with her baffling logic. She'd led investigators on a merry chase to universal studios, she said, in hopes that they'd stumble upon Caylee.

Casey: I'm coming back to places that are familiar to me that I know are familiar to her. Familiar situations that maybe...

Bianca Prieto: Casey and the truth have a problem. You know, everything that she said almost is a complete lie, or it's not checking out. Investigators can't find anything and they tell her, "We're gonna help you, but you need to tell us the truth."

After their confrontation at Universal Studios, investigators took Casey to the county jail, and charged her with child neglect, lying to the police, and obstructing an investigation.

But her problems were only beginning. Many more charges would follow -- Casey Anthony was about to be accused of doing the worst thing a mother can do to her child.

Just about everything Casey Anthony told investigators about the disappearance of her daughter, Caylee, had turned out to be a lie. But if investigators thought they would rattle a true confession out of her once she was in jail, they were wrong. From the county jail, Casey made an angry phone call to her parents to ask for her boyfriend's number.

Cindy: Well whose fault is your sitting in jail? Are you blaming me that you're sitting in jail?

Casey: Not my fault.

Cindy: Blame yourself for telling lies. What you mean it's not your fault? What do you mean it's not your fault, sweetheart? If you'd have told them the truth and not lied about everything they wouldn't...

Casey: Do me a favor, just tell me what Tony's number is. I don't want to talk to you right now. Forget it.

One of Casey's friends got on the line, hoping she could get through to Casey.

RonStucker: She's expressing absolutely no concern for the location of her child.

Dennis Murphy: Behavior of a frantic, anxious mom?

Ron Stucker: Absolutely not. Absolutely not.

That apparent lack of concern was noteworthy because as investigators began to interview Casey's friends and family, they started to piece together a jarring picture of what Casey was up to in those 30 days since Caylee went missing -- the image they got was not one of a concerned mother.

Ron Stucker: She goes and gets a new tattoo which says "Bella Vita," which means "beautiful life." She is text messaging and emailing her friends, setting up appointments do to things. And in none of those does she ever express concern about her child that is allegedly missing.

In fact, on that first evening after her daughter had disappeared -- June 16 -- Casey was spotted at a blockbuster video store, browsing for movies with a boyfriend, Anthony Lazzaro. He later told investigators that Casey never once mentioned anything about Caylee going missing.

Detective: No phone calls from babysitters?

Anthony Lazzaro: Nope. Like I said before, every time she'd talk on the phone she was pretty, not secretive about it, but you know.

Detective: Any conversation about her child at all?

Anthony Lazzaro: No.

Within hours of Casey's arrest on July 16, the story had gone national. And photos began to surface on the web, showing Casey partying and at clubs. These photos were taken the weekend of June 20 -- just four days after Caylee went missing.

To the Orange County sheriff, Kevin Beary... It was what Casey did in the days after her daughter went missing that spoke to him of the suspicion of her guilt.

Kevin Beary: The typical person, the legitimate parent, if you turn around in a store and you don't see your child, and then 20 seconds later you find them, you're huggin 'em and tellin' em, "Don't ever run away like that again." We didn't get any of those emotions.

And among the friends interviewed by police, one woman's story raised a different kind of red flag. The friend, Amy Huizenga, had lent Casey her car for a week in July. She told police that during that time, Casey stole a checkbook out of her glove compartment.

DennisMurphy: Her friend's checkbook?

BiancaPrieto: One of her best friends. The girl she had been spending all summer with.

Dennis Murphy: And she goes and has a shop-up on her friend.

BiancaPrieto: Right. You know, she goes to Target, buys a bunch of stuff. It's interesting. The shirt that she's wearing, with the blue hoodie with the number on the front that she's wearing when she's arrested, bought with Amy's money.

Now along with child neglect and lying to investigators, authorities were looking into possible charges of check fraud. But back to their missing child investigation.

Investigators interviewed the Anthony's next door neighbor, who remembered that sometime between June 17-20 -- just a couple days after Caylee disappeared -- Casey had backed up her car into the Anthony's garage. And she had come over to borrow a shovel.

Crime scene investigators descended on the Anthony home.

Ron Stucker: We had our cadaver dogs who were alerting on the car that had been abandoned. They were alerting in the parents' backyard. And they're already indicating to us that there's been a dead body in that trunk.

The search for a missing girl suddenly took on a darker undertone -- police were now looking for a body. They didn't find one yet, but in that car trunk police found something else significant -- hair that resembled Caylee's.

But while the evidence against Casey Anthony ratcheted up -- and with it plenty of public hostility -- her parents seemed to have a public about-face.

Her mother, who had placed that 911 call alluding to the smell of a dead body in the car, now had a different explanation.

Cindy: There was a bag of pizza for what 12 days in the back that stunk so bad. You know how hot it's been. That smell was terrible...

Cindy: It was our first visitation with Casey that actually gave us insight into what was going on with her.

George: I just wish you could have came to me sooner.

Casey: I wish I could've come to anyone sooner. I wish that, like I said, that none of this would have happened.

In those jailhouse visitations with Casey, which were recorded on video cameras, the Anthonys probed for answers on where Caylee could be.

Cindy: Do you think Zanny's acting by herself or does she have help?

Casey: I don't know, Mom. I haven't been able to talk to anybody. I don't know. I'm hoping that if there's people involved there's as many people that are dumb enough to open their mouths and say something.

And Casey told her brother, Lee, that she had a message for the public.

Casey: All I want is to see her, to hear her laugh, to see her smile, and just be with her family.

From the information they were able to glean from their daughter, George and Cindy now believed that Caylee was being held by a group of tough characters associated with the baby-sitter -- characters who had been threatening Casey, and who were now preventing her from talking.

At a bond hearing a week after her arrest, a tearful Casey watched as her parents told a judge they would do everything in their power to support their daughter, and find Caylee.

Cindy: There's only one or two reasons why Casey would be withholding something about Caylee. And I think it's something that someone is holding over her and threatening her in some way.

Bond was set at half-a-million dollars. Casey would remain in jail.

But the Anthony's belief that Caylee was still alive, being held by someone, was about to get a boost from an unlikely source.

George: Each moment that went by, it just - I found it harder and harder to believe that these guys were just going through motions. And I just, I couldn't accept that from them.

By August, the Anthonys - George and Cindy - were growing frustrated. The police, they believed, had given up on looking for their granddaughter, Caylee, and were intent on implicating their daughter, Casey, for murder. But public sentiment was turning against them.

BiancaPrieto: I mean, the protesters are egging them on.

Dennis Murphy: So, people have gathered to taunt the family?

BiancaPrieto: People have gathered. Yes. All hours of the night.// There was one woman who brought her little child out there, and a baby, two years old, is holding a sign that said, "Why would you wanna kill a child like me?"

One month after Caylee had gone missing, the besieged Anthonys got a boost from an unlikely source: a black-hatted, black-dudded bounty hunter from out west, named Leonard Padilla.

Padilla, a reality show veteran, made a public announcement about bailing casey out, and getting the real story out of her.

LeonardPadilla: I believe she's still alive. I believe she still can be found.

After five weeks in jail, Casey returned home. But just a few days later...

LeonardPadilla: I think she is a self-centered egotistical little spoiled brat.

It turns out, the bounty hunter got the same story from Casey that she'd given police, with some slight variations...

LeonardPadilla: She says, "Zenaida held me down. Samanatha, her sister, grabbed the baby put her in the car with the kids. Zenaida handed me a list. It's got 30 days instructions on what to tell the people."

DennisMurphy: Let's call it your baloney detector. Is it going off?

LeonardPadilla: Yeah.

DennisMurphy: And you called her on it at that point?

LeonardPadilla: Yeah. She says, "Get outta my house. You're not gonna talk to me like a cop. Get outta here."

Anchor: Busted again. Casey Anthony is back in jail tonight just a few hours ago, deputies descending on her parent's home and rearresting her, as the crowd as you can hear outside that home cheered."

But Padilla didn't have to wait too long to get his bail money back. A week after getting out of jail on her original child endangerment charges, Casey Anthony was arrested again -- this time for fraud -- those checks she had allegedly stolen from her friend's car.

Within hours though, the check fraud charges would become old news, as the orange county sheriff's office revealed the preliminary findings of its forensic investigation into what happened to Caylee.

Orange County Sheriff's Office, Captain Nieves: We had higher hopes of finding her alive, and that hope has somewhat diminished.

In their initial search, crime scene investigators from the sheriff's office had processed Casey's car, after a cadaver dog alerted them to a hit. They sent evidence from the car off to the FBI’s crime lab in Quantico.

Now, the results were back... And the conclusions were grim.

Among the findings by the FBI lab -- signs of human decomposition on that strand of hair taken from Casey's car trunk -- hair that DNA analysis showed could have come from Caylee or Casey. And that wasn't all.

Air samples from the car had also been sent to the University of Tennessee's forensic anthropology center, also known as the body farm, where researchers gather data on how bodies decay.

Dennis Murphy: And what did the car say to the lab people?

RonStucker: What it's telling us right now, based on the evidence that's been processed -- that, yes, there was a decomposing human body in that car.

The sheriff's office had also sent samples from that car trunk to the Oak Ridge national laboratory in Tennessee, and got back perhaps the most devastating findings of all... Elevated traces of chloroform found in the spare tire cover and trunk liner.

Chloroform?

Dennis Murphy: Help us connect the dots. When I think of chloroform, I just think of old movies where someone puts it in a rag, and puts it on the person's face to knock 'em out. Is there any other explanation, in our daily lives, of chloroform occurring, being found?

Ron Stucker: When we first got that, one of our investigators began to call chemical companies in the Orlando area and say, "Hey, can I get some chloroform?" Nobody could provide it to them. They were like, "Nobody even asked for this." And so it of course raised our curiosity of what it could be used for.

The presence of chloroform was also important because of something else detectives had discovered in the case.

They seized Casey's home computer, and discovered some disturbing searches. Someone had used the computer before Caylee disappeared to browse missing children's websites. Back in march, there were Google searches for "neck breaking" and "household weapons." And even more significantly...

Ron Stucker: It was on the computer is where we found that there were searchers for the word chloroform, and trying to find information about chloroform.

And there was more on that computer that would cause friends, who had uniformly agreed that the devoted young mother would never speak ill of Caylee -- to pause.

Investigators uncovered instant messages Casey had exchanged with a boyfriend, shortly before Caylee vanished. In the messages, Casey -- who worked sometimes at a club, wrote "spending the day with Caylee is 10 times more exhausting than working a 12-hour event."

Dennis Murphy: And uses the word "snot head"?

BiancaPrieto: Yeah. She calls --

Dennis Murphy: Not a mother's term of endearment?

BiancaPrieto: She calls Caylee snot head. Ya know, not a very loving term for a child.

And still more. On July 7th, Casey made this chilling entry on her MySpace page. It read, "What is given, can be taken away. Everyone lies. Everyone dies. Life will never be easy." There was also this eerie cartoon.

Dennis Murphy: What are you putting together about her?

BiancaPrieto: We don't know who this girl is. One thing that was very interesting, when we were trying to piece together a profile about her, is no one would talk.

Dennis Murphy: The best friends had clammed up?

BiancaPrieto: Yeah. No one. Friends wouldn't talk. The only people that were speaking on her behalf were George, Cindy, and Lee.

Her family was still standing by her, even after the flood of forensic evidence. On September 4, an anonymous donor once again posted bond on Casey Anthony. Hounded by protesters and media alike, she returned home to her parents.

People shouting: Casey, where's Caylee? Casey, did you kill Caylee?

But it was only a short matter of time before she would be back in jail again, this time on charges of murder.

On Oct. 14, prosecutors presented their murder case against Casey Anthony in front of a grand jury. Among the witnesses called, her father, George.

George: It's very emotional. I mean, no one wants to be called-- to talk about their family, in-- in such a way. But, I mean, it's-- I had to go do it. I just had to go do it.

Cindy: You had no choice.

George: I didn't have a choice.

Cindy: You had a subpoena.

For three months, the Anthonys had been bombarded with evidence that their missing granddaughter, Caylee, was dead, and that their daughter, Casey, was responsible. But they refused to believe any of it.

George: I just believe they're wrong, you know. And we've said in different conversations we've had with the Sheriff's department, "Prove it to me. Prove to me what you got." And by, you know something, they can't. Because my granddaughter is alive out there. And we're gonna find her. No matter how long it takes, I'm gonna find this little girl.

Prosecutor: The first count is first degree murder...

The grand jury indicted Casey for first degree murder - which in Florida, can mean either pre-meditated murder, or murder committed in the course of other, underlying crimes.

That same day, before she was arrested, Casey appeared at a press conference next to her attorney -- her heretofore chilly public persona suddenly showing cracks.

Jose: Casey is going through a nightmare and has been living a nightmare for the last several months. She has a missing child. She's also someone's child. This family has-- has-- has had to withstand something unlike anyone has ever seen.

Casey pleaded not guilty to all the charges against her. A month after the indictment, more than a thousand volunteers from all across the country -- gathered in Orlando to search for the body of Caylee Anthony.

They concentrated on a 25-mile radius -- where, according to signals off her cell phone, Casey had been in the days after caylee disappeared.

Melanie: I think people need closure. And I hope we find her today, but I don't think the results are what everyone want it to be.

Her family told us, up until this week, that they refused to give up hope that Caylee was still alive, kidnapped, they thought, by a woman named Zenaida.

Cindy: We believe that you know, Casey's been threatened. Our investigators are finding that everything that Casey has said has been true. They are putting, you know, everything together.

Dennis: Why do you think she lied when she did lie?

Cindy: I don't know. Why does anybody lie when they lie? I don't really know. I know why she lied to me for the month of June is because she didn't, she was worried about our safety. And she was worried about Caylee's safety.

The grandparents say that for months, hundreds of leads on Caylee's whereabouts have been ignored by the sheriff's office -- leads like this one -- a possible sighting from Nov. 16, when a tipster in Orlando took these photos at a local mall.

Cindy: There so many characteristics you know, that are Caylee. Are we 100 percent sure it's Caylee? No. But what what person would not want to follow that tip to the very end?

And they point out what they see as a major flaw in the prosecution's case -- that for Casey, a loving and devoted mother, to have killed her own daughter, just doesn't make sense.

Bianca Prieto: Everything we've been told is that Casey was a very loving mother. And it would be really hard to believe that she would do anything malicious to intentionally kill her child.

Dennis Murphy: You love your daughter. Is it possible there was an accident? Something happened and Casey covered it up badly?

Cindy: No -- Casey was always one, I mean, if Caylee fell and skinned her knee, you know, she was right there. If something happened, she'd been screaming bloody murder. She'd a call 911, you know, if something would happened to Caylee.

And if as that instant message chat suggested, Casey had felt burdened by Caylee, she could have easily given the child up to the grandparents -- she said as much in her interview with the police back in July.

Casey: If I wanted to really just get rid of her, I would've left her with my parents and I would've left. I would've moved out. I would've given my mom custody.

Even the ex-fiance says the Casey he sees today just doesn't jibe with the Casey he once knew... Something he's had to struggle with.

Jesse: The Casey that I knew, that I was with, that I was engaged to was not capable of doing that. But I've come to grips with the fact that this Casey, who she is now, I don't know her, and I don't know what she's capable of, and I don't know if she's capable of hurting her daughter.

Perhaps the only person who could answer that question for certain, still wasn't talking to authorities.

Then yesterday morning, even as Casey Anthony's attorney was appearing in court at a pre-trial hearing: A meter reader in a wooded area near the Anthony home was bending over to pick-up a plastic bag. A tiny skull tumbled out, and the case against the mother entered uncharted territory.

The gruesome discovery came on a day that was supposed to be quiet, in what has become the Casey Anthony media circus.

At 9:00 yesterday morning, lawyers were back in court for a routine hearing -- Casey's attorney, Jose Baez, requesting that her trial date be pushed back to march.

Bianca: no surprises, a 10-minute long hearing, and then within an hour, everything changed. There was this 911 call that came in.

11:00 caller 1: Yes, this is orange county utilities emergency dispatch, we found a human skull.

911: Oh my gosh.

Caller1: I know. Uh - we've got, uh, is it a meter reader?

Caller 2: yes.

Caller1: i'm going to let you speak right now to a representative from our field services utilities.

Caller 2: hi.

Caller 1: everything is recorded, here he is.

Caller2: how are you doing? A skull of -- that we believe is human.

911: what's the location?

Caller2: it's right off of suburban and Chickasaw in the Caylee Anthony area.

The call came after a meter reader for the water utility stumbled upon human remains in a patch of woods, just a quarter-mile from the Anthony home. He reported back to his office which then called 911.

Local reporter: You can see this is only a few blocks north of where the grandmother and Casey Anthony, the mother of missing Caylee Anthony, where they live at.

The remains, which authorities identified as those of a young child--gender undetermined--,were found inside a sealed plastic bag. When the meter reader picked up the bag, a skull rolled out. Neighbors who saw the remains say that duct tape was wrapped around the mouth of that skull.

Stucker: Of course we sent our investigators out right away but once they saw the scene and saw what was there we knew this may be a significant find.

The remains were found in a wetland area that was inacessible to search teams last summer. It had been waist deep in water due to record rainfall. But chief inspector stucker says the water levels may have actually helped the investigation.

Stucker: If these remains were submerged, it may have prevented animals from coming in and scattering it that we may have never found it

The Anthonys, who were on a plane back from California when the news spread, requested through their spokesperson, some privacy as they absorbed the latest developments.

Deputies whisked them away once their plane landed. They returned home this afternoon.

As for Casey, sources say that when she received news of the discovery, she suffered an anxiety attack and requested a sedative. The orange county jail has since placed her under psychological observation.

Reporter: are you concerned about your client's stability right now?

I'm concerned about my client, period and have been since day one.

After visiting his client for more than an hour yesterday, Casey's attorney cautioned the public to hold off on drawing any conclusions just yet.

Baez: there is still the chance that this might not be Caylee. So having said that, we're going to follow the rules.

Chief Stucker: A lot of the time frame is really going to depend on the integrity of the evidence, how quickly they can extract that and compare it to our known samples. We are hoping it will be within a couple of weeks

But the sheriff's office is leaving very little doubt as to what it thinks.

Late last night, officers from the sheriff's office returned once again to search the Anthony home -- declaring it a crime scene.

In the meantime, investigators continue the search today in the area around where the remains were found.

Bianca: this is a huge finding.// the sheriff's office had circumstantial evidence. They had the stain in the trunk, they had the smell in the trunk. And they had this missing child. They have a body now -- they have that, a body that may very well be the body of Caylee Marie Anthony.

The sheriff's office has said that a forensic examination of the remains has linked them to Caylee's home. And just today in court, the defense said that the color of the hair found among the remains, resembled Caylee's. So it asked for permission to send its own team to witness the autopsy. That request was denied. Linda Kenney Baden, the newest member of defense team, wasn't pleased with that decision.

Linda Baden: We just feel very sorry that the state and the county and the medical examiner felt that they could not open the process up for us to see.

The murder case of Casey Anthony has accelerated. All those questions waiting for answers. If it turns out to be the child? What happened to her? What is that ominous duct tape all about?

Questions, not least, about this enigmatic mother with a story authorities consider as fantastical as any told inside the children's theme parks. Orlando appreciates a good thrill ride and the trial of Casey Anthony promises to be all of that.

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.